The most popular Tiffany Style Diamonds shape has been the round brilliant because people believed it to be an "ideal cut" that displayed the most brilliance and sparkle in a loose diamond.
Factors important in selecting a fancy shaped diamond necklace include all of the 4Cs as they apply to the round shape.
The precise origin of engagement ring is still not truly known. However, it is believed that the first loose diamond ever discovered in South Africa was done so by a fifteen year old boy by the name of Erasmus Jacobs. While searching for a stick to clear a drain one day, he picked up a stone sparkling in the sunlight and gave it to his sister. It was seen by a friend of the family and was ultimately discovered to be a 21.25 carat stone.